Grinding head and grinding surface therefor



S C. RALYS GRINDING HEAD AND GRINDING'SURFACE THEREFOR Filed Feb. e, 1956 2 Sheets-Sheet 1 Fla. 2

IN VEN TOR. STANLEY c. RALYS ATTORNEY July 15, 1958 s c, R s 2,842,903

GRINDING HEAD AND GRINDING SURFACE THEREFOR Filed Feb. 6, 1956 '2 Sheets-Sheet 2 INVEN TOR. STANLEY C. RALY S A ORNEY GRINDENG HEAD AND GRINDING SURFACE THEREFDR Stanley C. Ralys Orange, Manse, assignor to Leavitt Machine Qompany, Gran e, Mass a corporation of Massachusetts Application February 6, 1956, Seriai No. 563,675

3 Claims. (Cl. 51-194) proved grinding head whereby chattering is reduced to a minimum.

A further object of the preesnt invention is the provision of a grinding head which is quickly and easily adaptable for grinding valves of any size.

A still further object of the present invention is a valve grinding head which is sturdy and adapted for heavy duty work.

The accompanying drawings illustrate the preferred forms of my invention and show the invention as applied to a valve grinding head particularly adapted to grind globe valves and the specific details shown in the drawings are for that particular type of grinding head.

In the drawings:

Fig. l is a top plan view of the grinding head with the grinding surfaces mounted on the headin position to grind a valve;

Fig. 2 is a side elevational view of the grinding head shown in Fig. 1;

Fig. 3 is a sectional side view taken along lines 3-3 of Fig. 1;

Fig. 4 is a side elevational view of the grinding surface particularly adapted to be used with the grinding head shown in Fig. 1;

Fig. 5 is a sectional view taken along line 5-5 of Fig. 4; and

Fig. 6 is a perspective view of the grinding surface shown in Fig. 4.

Referring more particularly to the drawings, the grinding head 1 comprises a central hub 3 having the integral legs 5 extending radially therefrom. The hub 3 has the bore 7 therein to permit the grinding head to be attached to the drive shaft of a grinding machine (not shown). The bore 7 is provided with a key-way 9 to be keyed to a drive shaft (not shown) for rotating the grinding head'l.

Each leg 5 is comprised of a bottom Wall 10 extending radially from the hub and the side walls 12 which are parallel to each other and extend upwardly from the bottom wall 10. A front wall or working plane 14 connects the two side walls 12 and is integral with and extends upwardly from the bottom wall 10. The working plane 14 is inclined with respect to the perpendicular to conform to the inclined plane of a valve seat to be ground.

The bottom wall 10 is common and integral with the legs 5 and the hub 3. straight and connect the inner ends of the. side walls 12 of adjacent legs 5 to each other. It will be noted that The connecting walls 15 are 2,842,903 Patented July 15, 1958 the grinding head 1 together with the legs 5 is in elfect a one-piece hollow structure having bottom and side walls and having an open top. This permits the grinding head to be sturdy and yet lightweight and inexpensive to manufacture.

It will be understood, however, that the present invention is not limited to a hollow grinding head but will encompass solid grinding heads as well as hollow ones.

Each leg 5 is provided with means for mounting the grinding surfaces 20 on the Working planes 14. In the drawings, the mounting means are shown as comprising separable snap fastener elements 16 mounted on the legs 12 in order to facilitate replacement of the grinding surfaces, as well be hereinafter explained.

Each grinding surface 20 is comprised of a sheet of abrasive material having a central grinding panel 22 and two flaps 24 extending on each side thereof. Each flap has a snap fastener element 26 thereon to be snapped into and out of engagement with a cooperating fastener element 16 on one of the legs 5. The grinding surfaces 20 are longer than the working planes 14 so that each grinding surface protrudes beyond the top and bottom edges of the working planes. This insures against the working plane 14 coming into contact with the valve seat and becoming damaged.

In the preferred form of the invention, resilient backing material 28, preferably comprising a rubber material, is interposed between the grinding surfaces 20 and the working plane 14. This backing material 28 may be permanently attached to the working plane 14, as shown in Figs. 1 to 3, or it may be permanently attached to the rear of the grinding surface 20 on the control panel 22 thereof, as shown in Figs. 4 to 6.

In operation, the hub 3 is keyed to a drive shaft (not shown) so that upper end of the grinding head is uppermost. The grinding surfaces 20 are then mounted on the working planes 14 of the legs 5. In placing the grinding surfaces 219 on each of the legs 5, the snap fastener elements 26; on the grinding surfaces are snapped on to the cooperating snap fastener elements 16 on each side wall 12 of the legs 5. This attaching operation is facilitated, as is also the reverse operation of disconnect ing the fastener elements, because the adjacent side walls of adjacent legs are related at an angle that is greater than a right angle and the straight line character of the connecting Walls 15 which unite the inner ends of these adjacent side walls leaves the space between the adjacent legs unobstructed. Hence the snap fastener elements 26 can be readily applied to and withdrawn from the snap fastener elements 16 by movements perpendicular to the surfaces of the side walls 12 without interference from any adjacent leg surface or other protuberance. When the grinding surfaces are worn out they can be removed by snapping open the snap fasteners and replacing with a fresh grinding surface. in the embodiment shown in Figs. 4 to 6, a fresh resilient backing is replaced with each grinding surface replaced.

It will be observed that the use of snap fasteners permits quick and easy replacement of the grinding surfaces 29. Placing of the cooperating snap fasteners 16 on the sides 12 of the legs 5 insures that they will not interfere with the grinding operation. Since the grinding surface extends beyond the top and bottom edges of the working plane 14, there is no danger of the working plane 14 coming into contact with the valve seat and thereby will prevent any damage to the valve seat or the grinding head.

The fact that the legs 5 are integral with hub 3 gives the grinding head 1 the sturdiness necessary to perform the heavy duty work involved. However, since in the preferred form of the head 1 is hollow, the head will require less material and hence will he inexpensive to make and will be of light weight so as to be capable of being easily carried.

It will be understood that the present invention is not limited to the details of construction recited in the foregoing description and shown in the accompanying drawings, except as appears hereafter in the claims.

What is claimed is:

1. A grinding head for a valve grinding machine comprising a hub, three legs extending radially therefrom in equidistantly spaced relation, each leg having a peripheral face tapered in conformity with the surface to be ground and having a pair of substantially parallel side walls connecting said peripheral face and extending inwardly therefrom, straight connecting walls integrally secured to the inner ends of the adjacent side walls of adjacent legs whereby the space between the adjacent side walls of adjacent legs is unobstructed, a flexible sheet abrasive strip element having a central panel engaged with the peripheral face of each leg andrhaving side extensions engaged with the side faces of each leg, and cooperating elements of separable snap fastening members carried by each of said extensions and each of said side walls mounting said abrasive strip elements on said legs, said elements comprising friction members engageable and disengageable by movement perpendicular to the surfaces of the sides of the legs, whereby said flexible sheet abrasive strip elements are readily removed and replaced by separation and connection of the elements of said fastening members in the unobstructed spaces between the adjacent side walls of adjacent legs.

2. A grinding head for a valve grinding machine comprising a hub, a bottom wall plate projecting radially from the lower periphery of said hub, three legs extending radially from the hub in equidistantly spaced relation, each leg having a peripheral face upstanding from the outer edge of the bottom wall plate and tapered in conformity with the surface to be ground and having a pair of substantially parallel side walls upstanding from said bottom wall plate, connecting said peripheral face and extending inwardly therefrom, straight connecting walls upstanding from said bottom wall plate and integrally secured to the inner ends of the adjacent side walls of adjacent legs whereby the space between the adjacent 1 on said legs, said elements comprising friction members engageable and disengageable by movement perpendicular to the surfaces of the sides of the legs, whereby said flexible sheet abrasive strip elements are readily removed and replaced by separation and connection of the elements of said fastening members in the unobstructed spaces between the adjacent side walls of adjacent legs.

3. A grinding head for a valve grinding machine comprising a hub, a bottom wall plate projecting radially from the lower periphery of said hub, a plurality of legs extending radially from the hub in equidistantly spaced relation, each leg having a peripheral face upstanding from the outer edge of the bottom wall plate and tapered in conformity with the surface to be ground and having a pair of substantially parallel side walls upstanding from said bottom wall plate, connecting said peripheral face and extending inwardly therefrom, the adjacent side walls of adjacent legs being related at an angle greater than an acute angle, straight connecting walls upstanding from said bottom wall plate and integrally secured to the inner ends of the adjacent side walls of adjacent legs whereby the space between the adjacent side walls of adjacent legs is unobstructed, a flexible sheet abrasive strip element having a central panel engaged with the peripheral face of each leg and having side extensions engaged with the side faces of each leg, and cooperating elements of separable snap fastening members carried by each of said extensions and each of said side walls mounting said abrasive strip elements on said legs, said elements comprising friction members engageable and disengageable by movement perpendicular to the surfaces of the sides of the legs, whereby said flexible sheet abrasive strip elements are readily removed and replaced by separation and connection of the elements of said fastening members in the unobstructed spaces between the adjacent side walls of adjacent legs.

References Cited in the file of this patent UNITED STATES PATENTS 1,964,240 Beard June 26, 1934 1,994,986 Drohan Mar. 19, 1935 2,133,612 Gallivan Oct. 18, 1938 2,206,355 Hubbard July 2, 1940 2,257,061 Morris Sept. 23, 1941 2,625,774 Tenny -QIan. 20, 1953 FOREIGN PATENTS 7 279,204 Great Britain Oct. 27, 1927 

